Those who follow Michael Bloomberg’s philanthropy know that clean energy and climate change have been major issues for the former NYC mayor and founder of Bloomberg LP.

From 2010 to 2013, then Mayor Bloomberg served as the chair of the C40 Cities Climate Leadership Group. In 2011, Bloomberg Philanthropies partnered with the Sierra Club to launch the Beyond Coal campaign, working to replace coal plants with clean energy sources. (In case you were wondering who's financing that "war on coal"—yup, it's a rich guy from New York City.)

And just last year, Bloomberg was named U.N. Special Envoy for Cities and Climate Change. Now, his foundation is stepping up once again, this time putting up $24 million over the next three years to help states and localities speed up their transition to clean energy sources.

That $24 million is being matched by Mark Heising and his wife Elizabeth Simons, who also have ties to the tech and financial sectors. Heising got his start designing and manufacturing cryptographic circuits, and now runs a private equity firm. Simons is the daughter of hedge fund billionaire James Simons.

Though not as well known as Bloomberg, Heising and Simons have been very active philanthropists the past few years; their foundation now holds more than $250 million in assets, and has given more than $80 million to a variety of causes, mostly since 2010. Their main environmental cause to this point appears to be sustainable fisheries and healthy oceans, and they’ve also made grants to organizations such the Center for Energy Efficiency and Renewable Technologies, the Clean Air Task Force, and Environmental Defense Fund, where Heising sits on the board.

Rather than giving the money directly to governments, the funds will be used to provide technical assistance, including economic forecasting and legal analysis, primarily for the dozen or so states that are willing to consider ambitious clean-energy plans.

The initiative will help cities and localities meet a target of reducing carbon-dioxide emissions from existing power plants by 30 percent from 2005 levels over the next 15 years, a goal that is part of President Obama’s Clean Power Plan, which is expected be brought to Congress this summer.

Bloomberg and Heising say the falling cost of natural gas and renewable energy, along with more energy-efficient technology, have put pressure on utility companies to rethink how they get their power. “With the price of clean power falling, and the potential costs of inaction on climate change steadily rising, the work of modernizing America’s power grid is both more feasible and urgent than ever,” said Bloomberg in a press release.

“The science on climate change makes it abundantly clear that carbon pollution poses a deep threat to society, to agriculture, and to nature—and that early action is required to avoid these threats. New technologies ensure that the solutions to climate change can be cost-effective. This initiative is designed to accelerate those solutions,” Heising added.